High performance tightener

ABSTRACT

A self stopping seat belt retractor is provided with a belt shaft for winding a seat belt thereonto and unwinding a wound seat belt therefrom and a housing rotatably supporting the belt shaft and having a locking device that includes a locking means for the belt shaft that can be controlled in a vehicle sensitive and/or belt sensitive manner into engagement with a toothed gearing system on that side of the housing. A tightening device operating on the belt shaft includes a drive wheel, which is, prior to the release of the tightening device, secured in a force-transmitting manner on the housing, is connectable upon release of the tightening device with the belt shaft, whereby the drive wheel of the tightening device is connectable via the locking device with the belt shaft for the transmission of force to the belt shaft.

BACKGROUND OF THE INVENTION

The invention relates to a self stopping or locking seat belt retractorwith a housing having a blocking device that includes at least oneblocking means for the belt shaft that can be controlled in a vehiclesensitive and/or belt sensitive manner into engagement with a toothedgearing system on the side of the housing, and a tightening deviceoperating on the belt shaft comprising a drive wheel that can be setinto rotation via a drive device, the drive wheel being connectable uponrelease of the tightening device with the belt shaft, whereby the drivewheel of the tightening device is connectable via the blocking devicewith the belt shaft for the transmission of force to the belt shaft andthe drive wheel is, prior to the release of the tightening device,secured in a force-transmitting manner on the housing of the seat beltretractor.

A self stopping seat belt retractor with the above-noted features isdescribed in EP 0 093 233. A rotation blade is provided to function as adrive wheel, the rotation blade being impinged by a gas streamintroduced thereonto and being connected with a ring rotatably supportedin a seat belt retractor housing. Pivotable bolts are arranged on theone side of the ring, the bolts being controllable into engagement withouter toothed lever gears fixedly secured to the belt shaft of the seatbelt retractor so that, upon release of the tightening device, therotatable ring drives the belt shaft via the bolts that have beencontrolled into engagement with the lever gear. At the same time, thering is a component of a rotatably arranged housing and this ring is,during normal operation of the seat belt retractor without release ofthe tightening device, fixedly secured to the housing via a returnmovement stop, which is effective for stopping movement in the beltunwinding direction, that is in the form of stop levers engaging thehousing. Upon blocking of the rotation of the belt shaft in the beltunwinding direction performed as a result of tasking by thebelt-sensitive and/or vehicle-sensitive control system, the boltsbetween the ring and the lever gear are coupled to a control disk thatis a component of the belt-sensitive/vehicle-sensitive control system,so that, upon tasking by the control system, the bolts disposed on thering are controlled into engagement with the lever gear. In this mannerthe belt shaft is blocked in its rotational movement, whereby a loadingon the belt shaft in the belt unwinding direction is diverted, via thebelt shaft, the lever gear, the belt, and the ring with the housing,into the supporting housing of the seat belt retractor.

The state of the art seat belt retractor thus puts into effect theprinciple that the vehicle-sensitive and/or belt-sensitive controlledblocking device that is available in any event is now drawn intoperforming the additional function of, as well, coupling the drive wheelof the tightening device to the belt shaft for the tightening operation.

The invention provides a solution to the challenge of improving thefunctioning principle of a seat belt retractor having the state of theart features.

SUMMARY OF THE INVENTION

The invention provides in its core concept that the drive wheelcomprises an inner toothed gearing system oriented for engagement by theblocking means of the blocking device secured on the belt shaft andthereby operates as a blocking toothed gearing system, and that thering-shaped drive wheel comprises, in addition to the inner toothedgearing system, an outer toothed gearing system for engagement with atleast one block lever on the housing that is maintained, via yieldingunder the bias of a spring, in engagement with the outer toothed gearingsystem, whereby, via the rotation of the drive wheel that is effected bythe release of the tightening device, the drive wheel is releasable fromthe housing and is connectable with the belt shaft in aforce-transmitting manner via the blocking means of the blocking device.

With this solution, the drive wheel of the tightening device isallocated the further function of a house-secured toothed gearing systemfor the blocking event of the seat belt retractor during its normaloperation involving no tasking by the tightening device, insofar as thedrive wheel comprises an inner toothed gearing system for engagement ofthe stop lever that is disposed in a conventional manner on the beltshaft. In this connection, the drive wheel is arranged in a non-rotatingdisposition relative to the housing of the seat belt retractor in thebelt retracting direction so that, via the engagement of the blockingmeans disposed on the belt shaft in the inside to other gearing systemof the drive wheel, the blocking force stemming from the belt shaft isconducted to the seat belt retractor housing via the blocking means andthe drive wheel. In this connection, there is, in addition to the innertoothed gearing system of the drive wheel, an outer toothed gearingsystem for engagement with an additional block lever fixedly secured tothe housing. At the same time, the drive wheel is arranged to berotatable in the belt unwinding direction so that, upon tasking by thetightening device via the rotation of the drive wheel as such iseffected via the controlled blocking means, the belt shaft is rotated aswell in the belt unwinding direction.

In this connection, in accordance with an embodiment of the invention,it is provided that the blocking toothed gearing system of the drivewheel and the block lever are arranged relative to one another such thata rotation of the drive wheel in the belt retracting direction isconstantly blocked and a rotation of the drive wheel in the beltunwinding direction is possible via an over-ratcheting of the blocklever by means of the blocking toothed gearing system of the drivewheel.

In a first embodiment of the invention, it is provided that the drivewheel is directly connectable in a force-transmitting manner with thebelt shaft via the blocking means arranged on the blocking device sothat the blocking means acts in a double function in normal operation ofthe seat belt retractor as it does in a tightening operation.

Alternatively, it can be provided that the blocking device for the beltshaft comprises, in addition to the blocking means effective forblocking the belt, a lever, mounted on the blocking device and capableof being activated by the drive wheel, for de-coupling the drive wheelon the blocking device. In this event, separate levers can be providedthat carry out in separated manner the blocking function and thecoupling function. This permits a customized arrangement of the levers.

In accordance with a first embodiment of the invention, it is providedthat the block link is arranged laterally adjacent the U-shank of thehousing and is pivotably mounted on the U-shank under a pre-tensioneffected via a rotation spring.

In an expedient embodiment of the invention, it can, however,alternatively be provided that the block lever is arranged in the planeof the U-shank in a recess arranged in the shank and is pivotablymounted in the recess, whereby a leaf spring is arranged between theblock lever and the edge of the recess. In this respect, a particularlyspace-saving configuration of the inventive seat belt retractor isconnected therewith.

For equal load distribution, more block links can be disposed on thehousing of the seat belt retractor around the circumference of the drivewheel. In this connection, a variation can be provided that the blocklevers are arranged on the drive wheel and a house-secured toothedgearing system is configured as a blocking toothed gearing system on thehousing.

To the extent that, with respect to the drive wheel, both a blockingtoothed gearing system for securing the drive wheel on the housing shankand, as well, the inside toothed gearing system for coupling to the beltshaft, are to be provided, it is provided that, in accordance with afirst embodiment of the invention, the blocking toothed gearing system,which is configured as an outside toothed gearing system, and the insidetoothed gearing system of the drive wheel are arranged in a plane. Tothe extent, as events may have it, that there is a space-savingarrangement of the toothed gearing systems already involved, there isproduced a particular production advantage if, in accordance with anembodiment of the invention, the outside toothed gearing system are, viaforming of the teeth of the inside toothed gearing system out of thering profile of the drive wheel, configured in a manner such that theoutside toothed gearing system and the inside toothed gearing systemform a toothed gearing system with unitary teeth.

In an alternative embodiment, it can be provided that the blockingtoothed gearing system, which is configured as an inside toothed gearingsystem, and the associated inside toothed gearing system of the drivewheel are arranged axially adjacent one another on the interior side ofthe ring profile of the drive wheel, whereby the block lever, which isdisposed in a secure manner in the house, is configured in a U-shapedmanner for engagement with the inside blocking toothed gearing systemand, as a consequence thereof, grips the drive wheel from a positionoutward thereof.

In accordance with an embodiment of the invention, it is also provided,in accordance with a different construction principle, to lay out thedrive wheel such that the drive wheel is operated in different waysbefore the tasking by the tightening device and after the tasking by thetightening device such that the quasi-house secured blocking toothedgearing system can operate as the belt shaft block. In this connection,it is provided, in accordance with an embodiment of the invention, thatthe drive wheel is secured on the housing via a blocking means that iscapable of being destroyed when subjected to loading and the drivedevice of the tightening device is configured such that, after theconclusion of the drive movement, a return movement of the drive devicein the belt unwinding direction is foreclosed such that the drive wheelis held in a non-rotating position via the blocked drive device andfunctions as the blocking toothed gearing system.

While the drive wheel, which is, for example, configured as acorrespondingly arranged shear pin before the release of the tighteningdevice, functions as an abutment for the engagement of the stop linksarranged on the profile head of the belt shaft during normal operationof the seat belt retractor, the drive wheel, which is configured viasuitable and known measures against a return rotation in the beltunwinding direction after the conclusion of the tightening operation, isitself so configured with respect to the blocking of the drive devicethat the drive wheel can receive the blocking force in the boltunwinding direction transmitted by the belt shaft.

To the extent, for example, as has been described in connection with theembodiments of the invention described hereinabove, that the drivedevice of the tightening device is configured as a known belt tighteneras described in DE 196 02 549 A1, it can be provided in order to fixedlysecure the drive wheel, that there is a blocking of the balls or,respectively, the drive body, in the drive channel effected via suitablepinching securement of the balls. To the extent that the drive device isconfigured, for example, as a cable tightener, measures for securing thedrive cable by means of suitable drive clamps or return movement stopsare available.

However, it can also be provided that the drive device itself is putinto operation for the securement of the drive wheel and, as well, forthe release of the tightening device, in lieu of the noted sheer pin, inthat, for example, the balls or, respectively, the drive body, arearranged on the drive wheel in a blocking manner such that, uponimpingement of the drive device in the tightening direction, a rotationof the drive wheel is possible while, however, a counterrotation—namely, in the belt unwinding directions—is not possible.

Since, before tasking by the tightening device, the coupling of the beltshaft with the drive wheel for the purpose of blocking the mechanism iseffected by the seat belt retractor-side sensor and this coupling isalso necessary for the transmission of the tightening movement, it isprovided, in accordance with an embodiment of the invention, that thereis a control element that is released by the tightening device forcoupling the blocking means of the blocking device to the drive wheel.Via the control element, which is released via the tightening device,the blocking means is coupled with the drive wheel as is the case withrespect to the belt blocking, so that a load transmitting connectionbetween the drive wheel and the belt shaft occurs and, via this loadtransmitting connection, the tightening movement from the tighteningdevice is transferred, as well, to the belt shaft. In this connection,the advantage is associated therewith that, after the thus-producedcoupling, the control element is not loaded during the tighteningprocess because, as is the case of a blocking event, the load transferis directly between the drive wheel and the belt shaft. To the extent inthe state of the art that there is typically a coupling required duringthe entire tightening process for transmitting force between the drivewheel and the belt shaft, such a coupling is no longer needed inconnection with the inventive solution.

In view of the configuration of the sensors, it can be provided in aconventional manner that an inertial mass engaging around the blockingdevice is provided for belt sensitive control of the blocking means, therelative movement of the inertial mass with respect to the rotationalmovement of the blocking device controlling the blocking means inengagement with the drive wheel, whereby an outer toothed gearing systemcan be provided for the inertial mass as a blocking toothed gearingsystem with which, during the normal operation of the seat beltretractor, the sensor lever of a vehicle sensitive sensor can be broughtinto engagement. If, therefore, the rotation of the inertial massremains behind the rotation of the belt shaft by reason of a too rapidbelt unwinding or if the rotational movement of the inertial mass isconstrained by the vehicle sensitive sensor, then the relative movementthat occurs between the inertial mass and the belt shaft is convertedinto controlling the block lever, which is disposed on the profile head,into engagement with the inside toothed gearing system of the drivewheel, whereby the load transferring connection between the belt shaftand the drive wheel is produced.

To the extent that the belt shaft and the drive wheel are to be coupledto one another via controlling of the stop levers disposed on theprofile head, various embodiments are provided for the control of thestop levers via an additional coupling lever that can be controlled intoengagement with the outside toothed gearing system of the inertial mass,which can then initiate the corresponding relative movement of theinertial mass with respect to the belt shaft.

In accordance with a first embodiment of the invention, is provided thatthe coupling lever is, upon release of the tightening device by means ofa special lever actuation, controllable into engagement with theblocking toothed gearing system of the inertial mass.

In this connection, it can be provided that the lever actuation isconfigured as a moveable actuator that moves the coupling lever, wherebythis actuator can be an electro-magnet or a piezo element or anothersuitable drive element.

Alternatively, it is provided that the actuator for actuating thecoupling lever is a pyrotechnically driven piston unit, whereby, toeffect actuation of the piston unit, a special pyrotechnic drive unitcan be provided; alternatively, it is also possible to connect thepiston unit to the pyrotechnic drive device of the tightening device sothat the piston unit, in order to actuate the coupling lever, can beimpinged by the drive device of the tightening device.

Also, further special pressure-controlled drive means can be consideredsuch as hydraulic drive possibilities, the production of a drive mediumby means of a burning down of a detonating fuse, additional Bowden cableactuators or actuators via a lever linkage as well as actuators with anexpanding pressure body such as are blown up by air or similar means.

In a further embodiment of the invention that is no longer based upon aninertial mass gripping around the blocking device, it is provided thatthe control element is a come-along lever that is disposed on the drivewheel and is controlled to respond to a housing component, thecome-along lever, upon rotation of the drive wheel, being controlledinto engagement with the blocking toothed gearing system of aninertially-controlled control disk operating as the blocking means andcoming out of engagement with the control disk in connection with theblocking, as effected by the control disk, of the blocking means withthe drive wheel. It is further provided that the control disk isarranged on a projection of the belt shaft on the outer side of ahousing cap that grips around the drive wheel and that the housing capis configured as a slide guide for the constrained guiding of thecome-along lever that protects through the housing cap, whereby it isprovided that the slide guide is so configured that the come-alonglever, upon conclusion of the control of the block lever into engagementwith the inner toothed gearing system of the drive wheel that iseffected via the rotation of the control disk relative to the profilehead, is sheared off.

In accordance with a further embodiment of the invention, it is providedthat the control element is a lever that can be rotatably swung out froma come along lever that extends into a pot-shaped inertial mass and isconnected with the drive wheel, the lever being controllable intoengagement with an inner toothed gearing system configured on the insideof the cap-shaped inertial mass. In this manner, it can be provided thatthe lever is pivotably disposed on a spring element secured on thecome-along piece, whereby the spring element comprises at least onespring arm that secures the lever in its inactive position. The springlever thus determines the tasking level in accordance with which, due tothe reason of the rotation of the drive wheel and the therewithconnected come along piece the lever is controlled into engagement withthe inner toothed gearing system of the inertial mass, so that theinertial mass is set into rotation; since, at the same time, uponrelease of the tightening device, the belt shaft is stationary or, inany event, rotates very slowly, such an event leads to a relativemovement between the inertial mass and the belt shaft so that theblocking means of the blocking device is controlled into engagement withthe inner toothed gearing system of the drive wheel, as a consequence ofwhich the direct load transferring connection between the drive wheeland the belt shaft is produced.

In view of the connection of the drive wheel with the inertial mass,which is, in this embodiment, again configured as cap-shaped, and theinside toothed gearing system thus configured thereon, a simplificationof the coupling configuration is provided for in that the controlelement is configured as a coupling member that is controllable by thedrive device of the tightening device to begin its drive movement in aninner toothed gearing system on the inside of the cap-shaped inertialmass, whereby this coupling member is comprised of a rod that isarranged to be longitudinally displaceable on the drive wheel by meansof the operation of the drive device, the rod extending, during itslongitudinal displacement, into engagement with the inner toothedgearing system of the inertial mass.

In accordance with an embodiment of the invention, it is provided thatthe drive wheel is arranged with its outer toothed gearing system on theoutside of a shank or leg of a U-shaped housing of a seat belt retractorand the block lever is disposed on the outside of the shank.

Alternatively, it can be provided that the drive wheel is arranged withits region that engages the drive device outside the U-shaped housing ofthe seat belt retractor on the outside of the shank and extends with anouter teeth-supporting flange through a support opening in the shank ofthe housing, whereby the block lever is disposed on the inside of theshank. In this manner, in an expedient way, the extension of the drivewheel that extends through the shank of the housing forms the rotationalsupport for the rotation of the drive wheel.

The invention comprises, however, other different space arrangements forthe function of the important construction elements.

The invention is, in particular, also deployable for the type of seatbelt retractors with a force-limiting device configured as a torsionbar, such type being known, for example, from DE 43 31 027 A1. Also, inthis seat belt retractor-belt tightening device combination the vehiclesensitive and/or belt sensitive-controlled blocking devices for the beltshaft and the coupling between the belt shaft and the drive wheel of thetightening device are arranged on different sides of the seat beltretractor housing. In such seat belt retractor-belt tightening devicecombinations provided with a torsion bar, the additional problem occursthat, following the conclusion of the tightening movement that iseffective in the belt unwinding direction, in order to carry out a forcelimitation, a rotation of the belt shaft in the belt retractingdirection is required and this is burdened or limited via the drive ofthe tightening device or, occasionally, can even be blocked thereby. Inthis connection, DE 43 31 027 A1 suggests, additionally, an expensiveand complicated device for de-coupling the drive wheel from the beltshaft after the conclusion of the tightening movement. With thedeployment of the basic concept of the invention in such seat beltretractor-belt tightening device combinations with force limitation, theadditional advantage is associated therewith that the force limitationis not hindered after the conclusion of the tightening movement.

Insofar that the invention provides, in one embodiment, that the torsionbar comprises a profile head that supports the blocking means and isgripped around by the inertial mass, it can be provided, in an expedientway in accordance with an embodiment of the invention, that the profilehead is connected with the belt shaft via shear pins as this basicconcept is known from DE 195 28 115 A1. In this respect, the movement ofthe belt shaft, during both normal unwinding and winding in of the beltas well as upon tasking by the tightening device, is transferred, viabridging over of the torsion bar, directly to the profile head. Afterthe conclusion of a tightening movement, there occurs, in associationwith corresponding unwinding loading on the belt shaft during anaccident event, a breakage of the shear pins so that the belt shaft cannow further rotate, due to the twisting of the torsion bar relative tothe blocked profile head. In this manner, the advantage arises that,during the force limitation process, a connection between the belt shaftand the tightening device no longer exists so that, to this extent, aswell, the limitations on the force limiting movement of the belt shaftpresent in the state of the art do not occur.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are further set forth in the drawings thatare hereinafter described. They show:

FIG. 1 a seat belt retractor with a tightening device in a total viewwith a partially exploded component group,

FIG. 2 the blocking side of the seat belt retractor with integrateddrive wheel in an exploded view,

FIG. 3 the subject matter of FIG. 2 as viewed in another viewingdirection,

FIG. 4 the tightening sensitive control system for the coupling of thebelt to the drive wheel in an individual detail illustration,

FIG. 5 a shank of the seat belt retractor housing with block levers forsecurement of the drive wheel,

FIG. 6 an arrangement for coupling the block levers of the profile headto the drive wheel in a schematic illustration,

FIG. 7 the arrangement according to FIG. 6 with a special, pyrotechnicdrive unit,

FIG. 8 the arrangement according to FIG. 6, by which the pyrotechnicdrive device of the tightening device delivers the drive impulse for theactivation of the coupling lever,

FIG. 9 another embodiment of the coupling of the stop lever of theprofile head to the drive wheel,

FIG. 10 the subject matter of FIG. 9 in a sectional side view,

FIG. 11 the control system for the coupling of the belt shaft to thedrive wheel in accordance with FIG. 1-3 in another embodiment,

FIG. 12 the securement of the drive wheel on a housing shank in anotherembodiment in a schematic illustration,

FIG. 13 the securement of the drive wheel on a housing shank in afurther embodiment in a schematic illustration,

FIG. 14 a-l in various embodiments, the respective arrangement to oneanother of the housing, belt shaft, drive wheel, as well as theblocking- and control-elements in a schematic illustration.

DESCRIPTION OF SPECIFIC EMBODIMENTS

The seat belt retractor illustrated in its totality in FIG. 1 has aU-shaped housing 10 in whose side U-shanks a belt shaft 12 is rotatablymounted; the belt of a not-illustrated seatbelt is wound up onto thebelt shaft 12.

While on a side of the belt shaft 12 a windup spring is arranged under ahousing cap 50, a drive wheel 13 of a tightening device is arranged onthe other side of the belt shaft 12, the drive wheel having a drivedevice 51 disposed relative thereto for setting the drive wheel 13 intorotation in the event of a release event of the tightening device. Thedrive device 51 is configured in the illustrated embodiment as a balltensioner according to DE 196 02 546 A1; to the extent that the drivedevice in its configuration does not count as part of the subject matterof the invention, a description thereof is to be had by reference to theabove-noted publication. Also, other drive devices are possible such as,for example, a drive via a drive cable wound onto the drive wheel. Inindividual details, the drive device 51 comprises a conduit housing 15,secured to the housing 10 via a securement cap 16, in which a propellingcharge as well as balls in the form of inertia bodies are arranged; in arelease event, the balls are driven by the gas created by ignition ofthe gas generator out of the conduit housing 15 so that these ballsenter into the cut-outs 14 of the drive wheel 13 and, consequently, setthe drive wheel 13 into rotation.

The drive wheel 13 has a projection 17 oriented toward the U-shank 11 ofthe housing 10, the projection projecting into a support opening 52configured in the U-shank of the housing 10. In this manner, a bearingflange 18 configured on the projection 17 lies against the outer side ofthe U-shank 11, while a thereon-connected bearing annulus 19 is arrangedin the plane of the bearing opening 52 so that the drive wheel 13 isrotatably supported in the U-shank 11 of the housing 10.

An outer toothed gearing system configured as a blocking toothed gearingsystem 20 is mounted on the region of the projection 17 that is adjacentthe bearing annulus 19 and in front of the belt shaft 12, the outertoothed gearing system having a block lever 21 pivotably arranged on theinner side of the U-shank 11 arranged relative thereto, the block leverbeing pre-tensioned by a spring 22 into its engagement position with theblocking toothed gearing system 20. In this manner, the toothed gearingsystems of the block lever 21 and the blocking toothed gearing system 20are configured such that a rotation of the drive wheel 13 in the beltretracting direction is continuously blocked and a rotation of the drivewheel 13 in the belt unwinding direction is possible throughover-ratcheting of the block lever 21 via the blocking toothed gearingsystem 20. Additionally, the drive wheel 13 comprises, in the region ofits projection 17, an inner toothed gearing system 40 for engaging theblocking means so that the drive wheel 13, which is secured on thehousing 10 via the block lever 21, operates as a load receiving,housing-side block for the block system of the seat belt retractor. Thecomponents for coupling the drive wheel 13 to the belt shaft 12 arehereinafter described in particular detail.

An alternative arrangement of the block levers 21 on the housing shank11 of the housing 10 is shown in FIG. 5; in this embodiment, two blocklevers 21 are arranged in the plane of the U-shank 11 of the housing 10and, in fact, are arranged in the recesses 60 present in the housingshank 11. The spring loading of the block levers 21 is effected via theleaf springs 61 arranged between the respective block levers 21 and theedge of the recess 60. As can be easily seen, a reduction of theconfiguration width of the seat belt retractor is connected therewith.

Insofar as concerns the configuration of the toothed gearing systems onthe drive wheel for the engagement of the block levers 21, the inventionsuggests various embodiments. Insofar in accordance with FIG. 1, theouter toothed gearing system 20 and the inner toothed gearing system 40are arranged in a plane, it is, in accordance with FIG. 12, suggested inan expedient manner to configure these toothed gearing systems 20, 40 ina single production step, in that the outer toothed gearing system 20 isformed via the stamping of the inner toothed gearing system 40 out ofthe ring profile of the drive wheel 13 so that a total unitary toothedgearing system is produced; this is depicted schematically in FIG. 12.

The coupling of the drive wheel 13 to the belt shaft 12 is explainedwith reference to an embodiment illustrated in FIGS. 2-4. As can beinitially seen in FIGS. 2 and 3, a profile head 23 is secured to therear side of the belt shaft oriented thereto, whereby a fixed connectionthat is not further illustrated is created between the profile head 23and the belt shaft 12, and such can be configured directly via thetorsion bar so that the belt shaft 12 and the profile head 23 rotaterespectively with one another.

To the extent that, in a configuration of a seat belt retractor with atorsion bar as the force limiting device such as is described, forexample, in DE 43 31 027 A1, the profile head 23 is connected in anon-rotating manner with the torsion bar extending in the interior ofthe belt shaft 12 and, to this extent, a relative rotation between theprofile head 23 and the belt shaft 12 is possible, push outs 24 radiallyspaced from one another are provided on the profile head 13, withnot-illustrated shear pins, connected with the belt shaft 12, beingdisposed on the push outs, so that, before a tasking by the torsion bar,the profile head 23 is directly connected with the belt shaft 12. Tworadially outwardly pivotable blocking levers configured as blockingmeans 25 are arranged in opposition to one another on the profile headvia which, in a hereinafter described manner, the blocking of the beltshaft 12 relative to the housing 10 is effected.

Insofar as the control of the blocking is, on the one hand, executed viaa belt sensitive control system and, on the other hand, executed via avehicle sensitive control system, the belt sensitive control systemcomprises an adapter 26 that is to be connected with the profile head 23via, preferably, a positive notch connection, with a so-called WS spring27 that determines the tasking level for the belt sensitive controlsystem being secured to the adapter 26. The outer, radially spacedspring end 28 is suspended on the inner side of an inertial mass 29 thatis configured in an annular shape and surrounds the profile head 23 withthe adapter 26. In order that the stop levers 25 of the profile head 23can extend radially outwardly, the inertial mass 29 comprisesrespectively opposed recesses 33 for the extension therethrough of thestop levers 25.

Additionally, a ring 55 is arranged on the outermost circumference ofthe inertial mass 29, whose outer teeth 56 are engaged by a block arm 32that is arranged with a vehicle sensor 31 upon tasking by the vehiclesensor and which, thereby, halts the inertial mass 29 in its movement.In this connection, the stop levers 25 are displaced in the blockfunction. The inertial mass 29 is, further, provided with an outertoothed gearing system 30 on its outer side which makes possible anadditional blocking of the belt shaft 12, in that the inertial massblocks upon their side movement into the toothed gearing system 40. Itwould therefore be alternatively possible, as the occasion arises topermit the stop arm 32 of the vehicle sensor 31 to also directly engagethe outer toothed gearing system 30.

As the inertial mass 29 operates not only as a component of the vehiclesensitive and the belt sensitive control systems but, additionally,performs the function in view of the coupling of the drive wheel 13, theinner volume of the ring-shaped inertial mass 29 is partitioned via aninner flange 34. A security plate 35 lies against the inner flange 34,the security plate being disposed in the ring-shaped inertial mass 29and being notch-engaged with the adapter 26 so that the inertial mass 29cannot be disassociated therefrom but is, however, relative to theprofile head 23 with the adapter 26, secured with the profile head 23for rotation therewith.

The inertial mass 29 is provided with an inner toothed gearing system 36in the region thereof which is axially opposed to the security plate 35.A come along part 37, which is secured via a positive connectionconfiguration 38 to the drive wheel 13, projects into this region of theinertial mass 29 provided with the inner toothed gearing system 36,whereby a stop spring 44 is secured to the come along piece 37. Atwo-armed coupling lever 41 with a centrally arranged crank pin 43 ismounted on the stop spring 44 for radially outward pivoting movement,the coupling lever having, on its outer end, a toothed gearing system 42that is arranged for engaging the inner toothed gearing system 36 of theinertial mass 29. The coupling lever 41 is held in its inactive positionby the spring arms 45 of the stop spring 44 in a manner such that it canfreely move relative to the inertial mass 29. In the event, nonetheless,that, upon a tasking by the tightening device there occurs a rotationalacceleration of the drive wheel 13 and the therewith associated comealong piece 37, the coupling lever 41 remains, due to its inertia,behind the rotational movement of the come along piece 37, whereby theforce of the spring arms 45 is overcome so that the coupling lever 41swings radially into engagement with the inner toothed gearing system36.

In normal operation of the seat belt retractor with unwinding andwinding in of the belt, there occurs, in a known manner, due to thetasking by the belt sensitive or vehicle sensitive control system, arelative rotation of the inertial mass 29 relative to the profile head23 and, consequently, relative to the belt shaft 12, in that either,upon the tasking by the vehicle sensitive control system, the inertialmass 29 is secured via engagement of the stop arm 32 of the vehiclesensor 31, while the belt shaft 12 further rotates, or in that, upon arapid unwinding of the belt, the inertial mass 29, due to its inertia,remains behind relative to a rapid rotation of the adapter 26 with theWS spring 27. In both events, the relative movement between the inertialmass 29 and the profile head 23 leads to a radial controlled movement ofthe stop lever 25 via the cutouts 33 of the inertial mass 29 untilengagement of the inner toothed gearing system 40 of the projection 17of the drive wheel 13. As the drive wheel 13 is secured due to thecontinuous engagement of the block lever 21 in the blocking toothedgearing system 20 on the housing 10, the belt shaft 12 is prevented froma rotation in the belt retracting direction and the loading that occursupon further belt unwinding is conducted away via the stop levers 25 andthe drive wheel 13 into the seat belt retractor housing 10. The drivewheel 13 is, to this extent, allocated a double function, in that it isalso called upon, as well, for configuring the belt blocking.

Insofar as the seat belt retractor comprises a torsion bar as a forcelimiting device, there occurs, in connection with a belt unwindingloading stemming from the blocked profile head 23 on the belt shaft 12,a shearing off of the shear pins from the push outs 24 of the profilehead 23 so that the belt shaft 12 can turn further by virtue of thetorsion bar tensioned on the belt shaft 12 and on the profile head 23 ina known manner relative to the blocked profile head 23 duringsimultaneous force reception through the torsion bar.

If it now occurs that there is a release of the tightening device and,consequently, a rotation of the drive wheel in the belt unwindingdirection, there is, initially, the rotation of the drive wheel 13 inthe belt unwinding direction is not blocked by the block levers 21staying in engagement with the blocking toothed gearing system 20because the toothed gearing system of the blocking toothed gearingsystem 20 and the spring-loaded block levers 21 are correspondinglyconfigured with one another such that the drive wheel 13 can turn in thebelt unwinding direction through over-ratcheting of the block lever 21via the blocking toothed gearing system 20.

The rotation of the drive wheel 13 leads to a tasking by the couplinglever 41, which is supported via the come along piece 37 on the drivewheel 13, the coupling lever 41, upon corresponding rotationalacceleration, being controlled into engagement with the inner toothedgearing system 36 of the inertial mass 29 so that the inertial mass 29is coupled to the rotation of the drive wheel 13. In this manner, thereexpediently occurs a relative movement between the rotating inertialmass 29 and the more or less in its inactive position belt shaft 20 withthe profile head 23, and this relative movement further leads to acontrol of the stop levers 25 into engagement with the inner toothedgearing system 40 of the drive wheel 13. As a consequence of this, aload transferring, direct coupling between the drive wheel 13 and theprofile head 23 is effected so that there is undertaken at the sametime, via the block device of the seat belt retractor, the transfer ofthe tightening rotation of the drive wheel 13 into a rotation of thebelt shaft 12 in the seat belt retractor device.

Alternative embodiments for controlling of the coupling levers thatbring about the coupling of the drive wheel 13 to the inertial mass 29and, consequently, the coupling engagement of the stop levers 25 of theprofile head 23 in the inner toothed gearing system 40, are described inconnection with FIGS. 6-8.

As can initially be seen in FIG. 6, a coupling lever 63 is rotatablymounted on the drive wheel such that the coupling lever can be swunginto engagement with the blocking toothed gearing system 30 of theinertial mass 29. This swinging in movement is executed via aschematically illustrated actuator 64 that can be configured, forexample, as an electro-magnet or a piezo element.

As can be seen in another embodiment in accordance with FIG. 7, theactuator can be configured, as well, as a piston unit 65 engaging thecoupling lever 63, the piston unit having a piston rod that engages thecoupling lever 63. The piston unit 65 is controlled via a specialpyrotechnic drive unit 66 which can be fired in common with the releaseof the tightening device.

With respect to the embodiment shown in FIG. 8, reference is had to adrive unit 68 for the tightening device for controlling the operation ofthe piston unit 65 in engaging the coupling lever 63, whereupon, forthis purpose, the drive unit 68 is connected via a gas pressure conduit69 with the piston unit 65. Upon the release of the drive unit 68, notonly the drive device 51 of the tightening device is impinged with gasbut, as well, a portion of the produced gas is branched off and led viathe gas pressure conduit 69 to the piston unit 65 so that the couplinglever 63 can correspondingly be controlled into engagement with theinertial mass 29.

A further embodiment for coupling the drive wheel 13 to the inertialmass 29 is shown in FIG. 11, whereby, here, a longitudinallydisplaceable pin 76 is arranged on the drive wheel 13 such that the pin76 extends into the path of the drive balls of the tightening device andis longitudinally displaced by the first-appearing ball and, inconnection with this longitudinal displacement, is moved into engagementwith the inner toothed gearing system 36 of the inertial mass 29 and,consequently, couples the drive wheel 13 and the inertial mass 29 to oneanother.

A further alternative embodiment for connecting the drive wheel 13 andthe belt shaft 12 is illustrated in FIGS. 9 and 10, whereby, inconnection with this embodiment, no pot-shaped inertial mass isprovided. In this embodiment there is a U-shaped housing cap 70 thatgrips around the drive wheel 13 arranged on the U-shank 11 of thehousing 10, the outer side of such housing cap having disposed thereatan inertia-controlled control disk 71 mounted on a belt shaft projection75 extending through the housing cap 70. The control plate 71 comprises,on its outer circumference, a locking toothed gearing system 74 that canbe arranged relative to a vehicle sensitive sensor. A come along lever72 is pivotably mounted on the drive wheel 13, the come along leverextending through a slot guide 73 configured in the housing cap 70 andbeing oriented for engagement with the blocking toothed gearing system74 of the control plate 71. The guide slot 73 is configured such that,upon the beginning rotation of the drive wheel 13, the come along lever72 is brought, via the secured guide slot 73, into engagement with theblocking toothed gearing system 74 of the control plate 71 and thecontrol plate 71 thereby, via its rotation, effects correspondingrotation of the drive wheel 13. In this connection, there occurs arelative rotation of the control plate 71 and the profile head 23which—as described—leads to a control of the stop levers 25. At the endof this control path, the come along lever 72 contacts the end of theguide slot 73 so that, at this position, the come along lever 72 issheared off and, consequently, the coupling of the drive wheel 13 to thecontrol plate 71 is again ceased; this coupling is, during the transferof the tightening movement after the engagement of the stop levers 25 inthe inner toothed gearing system 40 of the drive wheel 13, no longerrequired.

Different possibilities are shown in FIGS. 14 a-l for the components ofthe seat belt retractor necessary for its configuration such as thehousing, belt shaft, drive wheel, as well as the blocking and controlelements that can be arranged in various positions relative to oneanother; from this, it is clear that the invention is usable in allconceivable, configuration-dictated arrangements of the individual partsof a seat belt retractor and is not limited in their usage.

FIG. 14 a shows, initially, in a schematic illustration, an arrangementin which the tightening gear 13 with a bearing location 80 for the beltshaft 12 is disposed interiorly of a housing shank 11 of the U-shapedhousing 10, whereby the outer toothed gearing system 20 for connectionof the housing side-mounted block lever 21 and the inner toothed gearingsystem 40 for engagement of the belt blocking (profile head 23, stoplevers 25) are oriented toward the belt shaft 12.

The embodiment shown in FIG. 14 b differs in that the outer toothedgearing system 20 with the block levers 21 and the inner toothed gearingsystem 40 with the belt blocking 23, 25 are disposed on different sidesof the drive wheel 13, whereby the drive wheel is arranged to meshinglyengage the inner toothed gearing system 40 in order to thereby save onthe axial component length.

The embodiment illustrated in FIG. 14 c is that of a seat belt retractorsimilar to that shown in the illustration in FIG. 14 a, whereby thedrive wheel 13 is arranged interiorly adjacent the belt shaft 12 and thetoothed gearing systems 20, 40 are configured outwardly; in thisconnection, a blocking abutment is created.

The embodiment shown in FIG. 14 d is similar to that shown in FIG. 14 b,whereby, now, the drive wheel 13 with inner toothed gearing system 40and the outer toothed gearing system 20 with block levers 21 arearranged on different sides of the housing shank 11, whereby the drivewheel 13 is interiorly of the housing shank 11. An additional housecomponent 81 configured as an abutment for the stop lever 21 is providedon the U-shank 11 of the housing.

The embodiment shown in FIG. 14 e essentially shows an inversion of theembodiment shown in FIG. 14 d, whereby, now, the drive wheel 13 isarranged exteriorly of the housing shank 11 and the toothed gearingsystems 40, 20 of the drive wheel 13, which lie in a plane, are arrangedbetween the housing shank 11 and the belt shaft 12.

The embodiment shown in FIG. 14 f corresponds to the embodimentillustrated in FIG. 14 e, whereby an exchange of the constructionelements from the interior to the exterior is undertaken, in that thedrive wheel 13 is arranged between the housing shank 11 and the beltshaft 12 and the remaining elements are arranged exteriorly of thehousing 10. The block lever 21 is, in accordance with FIG. 14 d, againsupported against an additional housing component 81.

The embodiment illustrated in FIG. 14 g corresponds to that shown in 14e with the measure that the outer toothed gearing system 20 with theblocking lever 21 is arranged between the housing shank 11 and the beltshaft 12, while the drive wheel 13 with the thereto connected innertoothed gearing system 40 with the belt blocking 23, 25 is arrangedexteriorly of the housing 10.

In the hereinafter following still-to-be described embodiments accordingto FIGS. 14 h-14 l, there is, in addition to the U-shaped housing 10, ashas already been described in connection with FIGS. 14 d, and 14 f, anadditional housing component 81 on a U-shank 11 of the housing thatoperates as an abutment for the stop lever 21 so that, respectively, thestop lever 21 is mounted on this additional housing component 81. Inthis connection, in the embodiment in accordance with FIG. 14 h, thereis shown an inversion of the arrangement shown in FIG. 14 c, whereby thebelt blocking 23, 25 are arranged within the housing 10 and theremaining construction components are arranged exteriorly of the housing10.

In the embodiment illustrated in Figure i, an embodiment identical tothat shown in FIG. 14 b has been selected, whereby the correspondingelements of the drive wheel 13 with the associated blocking elements arearranged exteriorly of the housing 10.

The embodiment shown in FIG. 14 j corresponds once again to theembodiment shown in FIG. 14 a with a side-inverted arrangement of theconstruction elements, such being collectively disposed exteriorly ofthe housing 10.

The foregoing corresponds as well for the embodiments shown in FIGS. 14k and 14 l, such illustrations showing, in a manner analogous to theabove description, alternative arrangements.

The features of the subject matter of this case as set forth in theherein above description, the patent claims, the summary, and thedrawings, can be important individually or in desired combinations withone another in order to realize the invention in its various forms.

The specification incorporates by reference the disclosure ofPCT/EP03/03271 filed 28 Mar. 2003 and German Patent Application 102 13906.7 filed 28 Mar. 2002.

The present invention is, of course, in no way restricted to thespecific disclosure of the specification and drawings, but alsoencompasses any modifications within the scope of the appended claims.

1. A self stopping seat belt retractor, comprising: a belt shaft (12)for winding a seat belt thereonto and unwinding a wound seat belttherefrom; a housing (10) rotatably supporting the belt shaft (12) andhaving a blocking device (23) that includes at least one blocking means(25) for the belt shaft (12) that can be controlled in a vehiclesensitive and/or belt sensitive manner into engagement with a toothedgearing system on the side of the housing and having at least one blocklever (21); a drive device (51); and a tightening device releasable uponthe occurrence of a specified event to initiate blocking of the beltshaft (12) against further rotation thereof in the seat belt unwindingdirection, the tightening device operating on the belt shaft (12) andincluding a drive wheel (13) that can be set into rotation via the drivedevice (51), the drive wheel being connectable upon release of thetightening device with the belt shaft (12), whereby the drive wheel (13)of the tightening device is connectable via the blocking device (23)with the belt shaft (12) for the transmission of force to the belt shaftand the drive wheel (13) is, prior to the release of the tighteningdevice, secured in a force-transmitting manner on the housing (10) ofthe seat belt retractor, the drive wheel (13) having an inner toothedgearing system (40) that is oriented for engagement by the blockingmeans (25) of the blocking device (23) secured on the belt shaft (12)and that operates as a blocking toothed gearing system and an outertoothed gearing system (20) for engagement with the at least one blocklever (21) on the housing (10) that is maintained, via yielding underthe bias of a spring, in engagement with the outer toothed gearingsystem (20), whereby, via the rotation of the drive wheel (13) that iseffected by the release of the tightening device, the drive wheel (13)is releasable from the housing (10) and is connectable with the beltshaft (12) in a force-transmitting manner via the blocking means (25) ofthe blocking device, and wherein the drive wheel (13) is directlyconnectable with the belt shaft (12) via the blocking means (25) of theblocking device (23).
 2. A seat belt retractor according to claim 1,wherein the outer toothed gearing system (20) of the drive wheel (13)and the block lever (21) are configured relative to each other such thata rotation of the drive wheel (13) in the belt retracting direction iscontinuously blocked and a rotation of the drive wheel (13) in the beltunwinding direction is possible through over-ratcheting of the blocklever (21) via the blocking toothed gearing system (20) of the drivewheel (13).
 3. A seat belt retractor according to claim 1, wherein theblocking device (23) for the belt shaft (12) comprises, in addition tothe blocking means (25) effective for blocking the belt shaft (12), alever mounted on the blocking device (23) and activatable by the drivewheel (13) for coupling the drive wheel (13) to the blocking device(23).
 4. A seat belt retractor according to claim 1, wherein the housing(10) includes a U-shank (11) and the block lever (21) is arrangedadjacent the U-shank (11) of the housing (10) and is pivotably mountedon the U-shank (11) subject to a pre-tension applied by a rotationspring (22).
 5. A seat belt retractor according to claim 1, whereinseveral block levers (21) are mounted on the housing (10) of the seatbelt retractor on the circumference of the drive wheel (13).
 6. A seatbelt retractor according to claim 1, wherein the outer toothed gearingsystem (20) and the inner toothed gearing system (40) of the drive wheel(13) are arranged in a plane.
 7. A seat belt retractor according toclaim 1, wherein the outside toothed gearing system (20) and the innertoothed gearing system (40) are, via forming of the teeth of the insidetoothed gearing system (40) out of the ring profile of the drive wheel(13), configured in a manner such that the outside toothed gearingsystem (20) and the inside toothed gearing system (40) form a toothedgearing system with unitary teeth.
 8. A seat belt retractor according toclaim 1, wherein the drive wheel (13) is secured on the housing (10) viaa blocking means that is capable of being destroyed when subject toloading and the drive device (51) of the tightening device is configuredsuch that, after the conclusion of the drive movement, a return movementof the drive device (51) in the belt unwinding direction is foreclosedsuch that the drive wheel (13) is held in a non-rotating position viathe drive device (51) that is blocked and functions as the blockingtoothed gearing system.
 9. A seat belt retractor according to claim 1,and further comprising a control element (63, 72, 41, 76) that isreleased by the tightening device for coupling the blocking means (25)of the blocking device (23) to the drive wheel.
 10. A seat beltretractor according to claim 1, wherein, for a vehicle sensitive controlof the blocking device (23), an inertial mass (29) that grips around theblocking device is provided whose relative movement with respect to therotational movement of the belt shaft (12) controls the blocking means(25) into engagement with the drive wheel (13).
 11. A seat beltretractor according to claim 1, and further comprising an inertial mass(29) arranged relative to a blocking toothed gearing system (30) withwhich a sensor lever (31) of a vehicle sensitive sensor (30) can bebrought into engagement.
 12. A seat belt retractor according to claim 1,wherein the drive wheel (13) with its blocking toothed gearing system(20) is mounted on the outer side of a U-shank (11) of the housing (10)of the seat belt retractor and the block lever (21) is mounted on theouter side of the shank (11).
 13. A seat belt retractor according toclaim 1, wherein the housing (10) includes a U-shaped shank (11), thedrive wheel (13) is arranged with its region that engages the drivedevice (51) on the outside of the U-shank (11) and extends through theU-shank (11) via a support opening (52) therein with a projection (17)that supports the outer toothed gearing system (20), and the outertoothed gearing system (20) is mounted on the inner side of the U-shank(11).
 14. A seat belt retractor according to claim 4, wherein the blocklever (21) is arranged in the plane of the U-shank (11) in a recess (60)formed thereon and is pivotably mounted in the recess (60), whereby aleaf spring (61) is arranged between the block lever (21) and the edgeof the recess.
 15. A seat belt retractor according to claim 9, furthercomprising an inertial mass (29) is arranged relative to a blockingtoothed gearing system (30) with which a sensor lever (31) of a vehiclesensitive sensor (30) can be brought into engagement and the controlelement is a coupling lever (63) that can be controlled into engagementwith the blocking toothed gearing system (30) of the inertial mass (29).16. A seat belt retractor according to claim 9, wherein the controlelement is formed as a come along lever (72) mounted on the drive wheel(13) and guided in a constrained manner by a housing piece (70), thecome along lever being constrained into engagement with the blockingtoothed gearing system (74) of a control plate (71) of the block means(25) upon rotation of the drive wheel (13) and thereafter moving out ofengagement with the control plate (71) in connection with the blockingof the block means (25) with the drive wheel (13) effected via thecontrol plate (71).
 17. A seat belt retractor according to claim 9,wherein the control element is a coupling lever (41) that is rotatablymounted on a come along lever (37) that extends into a pot-shapedinertial mass (29) and is connected with the drive wheel (13), thecoupling lever being controllable into engagement with an inner toothedgearing system (36) configured on the inside of the pot-shaped inertialmass (29).
 18. A seat belt retractor according to claim 9, and furthercomprising an inertial mass (29) arranged relative to a blocking toothedgearing system (30) with which a sensor lever (31) of a vehiclesensitive sensor (30) can be brought into engagement and the controlelement is a coupling member (76) that is controllable into engagementwith an inner toothed gearing system (36) of the inertial mass (29) bythe drive device (51) of the tightening device upon the movement of thedrive device to begin its rotation.
 19. A seat belt retractor accordingto claim 15, wherein the coupling lever (63) can be controlled, uponrelease of the tightening device, into engagement with the blockingtoothed gearing system (30) of the inertial mass (29) by means of aspecial lever actuator.
 20. A seat belt retractor according to claim 15,wherein the lever actuator is an actuator (64) operative to move thecoupling lever (63).
 21. A seat belt retractor according to claim 20,wherein the actuator (64) is an electro-magnet, a piezo element, or apyrotechnically driven piston unit (65).
 22. A seat belt retractoraccording to claim 21, wherein when the actuator is a piston unit, toactuate the piston unit (65), a special pyrotechnic drive unit (66) isprovided.
 23. A seat belt retractor according to claim 21, wherein whenthe actuator is a piston unit, the piston unit (65) is connected to thepyrotechnic drive unit (68) of the tightening device and is impactedthereby.
 24. A seat belt retractor according to claim 16, wherein thecontrol plate (71) is disposed, on the outer side of a housing cap (70)that grips around the drive wheel (13), on a belt shaft projection (75)of the belt shaft and a guide slot (73) is configured in the housing cap(70) for constrained guiding of the come along lever (72) that extendsthrough the housing cap (70).
 25. A seat belt retractor according toclaim 24, wherein the guide slot (73) is configured such that the comealong lever (72) is sheared off after the conclusion of the controlledengagement, effected via the relative rotation of the control plate (71)with respect to the profile head (23), of the stop lever (25) with theinside toothed gearing system (40) of the drive wheel (13).
 26. A sealbelt retractor according to claim 17, wherein the coupling lever (41) ispivotably disposed on a spring element (44) secured on the come-alongpiece (37).
 27. A seat belt retractor according to claim 17, wherein thespring element (44) comprises at least one spring arm (45) that securesthe coupling lever (41) in its inactive position.
 28. A seat beltretractor according to claim 18, wherein the coupling member iscomprised of a longitudinally displaceable pin (76) arranged on thedrive wheel (13) that is longitudinally displaceable by the drive device(51), the pin (76), via its longitudinal displacement, being moved intoengagement with the inner toothed gearing system (36) of the inertialmass
 29. 29. A seat belt retractor according to claim 13, wherein theprojection (17) extending through the U-shank (11) of the housing (10)forms the rotational support for the rotation of the drive wheel (13).30. A self stopping seat belt retractor, comprising: a belt shaft (12)for winding a seat belt thereonto and unwinding a wound seat belttherefrom; a housing (10) rotatably supporting the belt shaft (12) andhaving a blocking device (23) that includes at least one blocking means(25) for the belt shaft (12) that can be controlled in a vehiclesensitive and/or belt sensitive manner into engagement with a toothedgearing system on the side of the housing and having at least one blocklever (21); a drive device (51); a tightening device releasable upon theoccurrence of a specified event to initiate blocking of the belt shaft(12) against further rotation thereof in the seat belt unwindingdirection, the tightening device operating on the belt shaft (12) andincluding a drive wheel (13) that can be set into rotation via the drivedevice (51), the drive wheel being connectable upon release of thetightening device with the belt shaft (12), whereby the drive wheel (13)of the tightening device is connectable via a blocking device (23) withthe belt shaft (12) for the transmission of force to the belt shaft andthe drive wheel (13) is, prior to the release of the tightening device,secured in a force-transmitting manner on the housing (10) of the seatbelt retractor, the drive wheel (13) having an inner toothed gearingsystem (40) that is oriented for engagement by the blocking means (25)of the blocking device (23) secured on the belt shaft (12) and thatoperates as a blocking toothed gearing system and an outer toothedgearing system (20) for engagement with the at least one block lever(21) on the housing (10) that is maintained, via yielding under the biasof a spring, in engagement with the outer toothed gearing system (20),whereby, via the rotation of the drive wheel (13) that is effected bythe release of the tightening device, the drive wheel (13) is releasablefrom the housing (10) and is connectable with the belt shaft (12) in aforce-transmitting manner via the blocking means (25) of the blockingdevice; an inertial mass (29); and a force limiting device in the formof a torsion bar connected, on one side, with the belt shaft (12) andsupporting, on the other side, the blocking means (25) of the blockingdevice (23), the torsion bar including a profile head (23) that isgripped around by the inertial mass (29) and that supports the blockingmeans (25).
 31. A seat belt retractor according to claim 30, wherein theprofile head (23) is connected with the belt shaft (12) via a specialconnecting means.
 32. A self stopping seat belt retractor, comprising: abelt shaft (12) for winding a seat belt thereonto and unwinding a woundseat belt therefrom; a housing (10) rotatably supporting the belt shaft(12) and having a blocking device (23) that includes at least oneblocking means (25) for the belt shaft (12) that can be controlled in avehicle sensitive and/or belt sensitive manner into engagement with atoothed gearing system on the side of the housing and having at leastone block lever (21); a drive device (51); and a tightening devicereleasable upon the occurrence of a specified event to initiate blockingof the belt shaft (12) against further rotation thereof in the seat beltunwinding direction, the tightening device operating on the belt shaft(12) and including a drive wheel (13) that can be set into rotation viathe drive device (51), the drive wheel being connectable upon release ofthe tightening device with the belt shaft (12), whereby the drive wheel(13) of the tightening device is connectable via the blocking device(23) with the belt shaft (12) for the transmission of force to the beltshaft and the drive wheel (13) is, prior to the release of thetightening device, secured in a force-transmitting manner on the housing(10) of the seat belt retractor, the drive wheel (13) having an innertoothed gearing system (40) that is oriented for engagement by theblocking means (25) of the blocking device (23) secured on the beltshaft (12) and that operates as a blocking toothed gearing system and anouter toothed gearing system (20) for engagement with the at least oneblock lever (21) on the housing (10) that is maintained, via yieldingunder the bias of a spring, in engagement with the outer toothed gearingsystem (20), whereby, via the rotation of the drive wheel (13) that iseffected by the release of the tightening device, the drive wheel (13)is releasable from the housing (10) and is connectable with the beltshaft (12) in a force-transmitting manner via the blocking means (25) ofthe blocking device, wherein the blocking device (23) for the belt shaft(12) comprises, in addition to the blocking means (25) effective forblocking the belt shaft (12), a lever mounted on the blocking device(23) and activatable by the drive wheel (13) for coupling the drivewheel (13) to the blocking device (23).
 33. A self stopping seat beltretractor, comprising: a belt shaft (12) for winding a seat beltthereonto and unwinding a wound seat belt therefrom; a housing (10)rotatably supporting the belt shaft (12) and having a blocking device(23) that includes at least one blocking means (25) for the belt shaft(12) that can be controlled in a vehicle sensitive and/or belt sensitivemanner into engagement with a toothed gearing system on the side of thehousing and having at least one block lever (21); a drive device (51);and a tightening device releasable upon the occurrence of a specifiedevent to initiate blocking of the belt shaft (12) against furtherrotation thereof in the seat belt unwinding direction, the tighteningdevice operating on the belt shaft (12) and including a drive wheel (13)that can be set into rotation via the drive device (51), the drive wheelbeing connectable upon release of the tightening device with the beltshaft (12), whereby the drive wheel (13) of the tightening device isconnectable via the blocking device (23) with the belt shaft (12) forthe transmission of force to the belt shaft and the drive wheel (13) is,prior to the release of the tightening device, secured in aforce-transmitting manner on the housing (10) of the seat beltretractor, the drive wheel (13) having an inner toothed gearing system(40) that is oriented for engagement by the blocking means (25) of theblocking device (23) secured on the belt shaft (12) and that operates asa blocking toothed gearing system and an outer toothed gearing system(20) for engagement with the at least one block lever (21) on thehousing (10) that is maintained, via yielding under the bias of aspring, in engagement with the outer toothed gearing system (20),whereby, via the rotation of the drive wheel (13) that is effected bythe release of the tightening device, the drive wheel (13) is releasablefrom the housing (10) and is connectable with the bell shaft (12) in aforce-transmitting manner via the blocking means (25) of the blockingdevice, and further comprising a control element (63,72,41,76) that isreleased by the tightening device for coupling the blocking means (25)of the blocking device (23) to the drive wheel.